The present invention relates generally to scaffolds and staging systems for supporting workmen and materials during the erecting, repairing, painting and the like of structures and, more particularly to a coupler system for interconnecting coaxially aligned hand rail sections.
Staging systems are used to support workmen and materials during the performance of a variety of tasks at elevated heights above the ground. A number of methods know to those skilled in the art are available to lift the staging and support it at the desired working elevation. Normally, these staging systems include some type of hand rail system to protect the workmen from falling or otherwise injuring themselves while performing tasks at some level above ground. In addition to the hand rail system, staging generally includes a platform to which are attached a number of vertical posts which are connected to hand rails. Typically, vertical posts are located at each end of the platform and several vertical posts are located between those end posts along the edges of the platform. As many as 6 or 7 vertical supports may be located along one platform side, depending on the length of the platform. Brackets are fitted on the posts to support the hand rail system. Once the brackets are positioned on the posts, hand rail sections are horizontally inserted through a series of brackets on each side of the platform to form the hand rail of the staging system.
The components of a staging system are usually transported by truck to a delivery point or for assembly at a job site. These hand rail sections are typically shipped in 10 to 40 foot lengths. As the rails increase in length, the difficulties associated with shipping increase. For example, the long lengths make it more difficult to adequately package the rails for shipping, resulting in more likelihood of damage to the rails in transit. In addition, as the lengths of the rail sections increase, it becomes more difficult to slide the handrail through the series of brackets mounted at the tops of the vertical posts. Longer rails may also be more difficult to handle when there is only limited space available for assembly of the hand rails. When disassembling the staging, the long lengths of hand rails are equally difficult to remove from the brackets. These difficulties in shipping and assembly repeat themselves when the staging is disassembled and moved to a different location for reassembly.
One way to overcome these problems is to assemble the staging using shorter hand rail sections that are coupled together. Various coupling devices are currently available. For example, U.S. Pat. No. 1,115,912 issued to Dodson in 1914 and entitled "Pipe-Coupling" discloses joining axially spaced pipe sections using a threaded coupler and a threaded bushing. Similarly, U.S. Pat. No. 2,169,069 issued to Kaufman in 1939 and entitled "Pipe Union and Fitting" discloses the use of threaded couplers to join a pair of axially spaced pipe sections. Although this type of coupler can join coaxially aligned lengths of pipe, it requires that threads be machined onto the ends of the rail sections. This requirement for threaded ends results in increased expense and assembly time to join the sections. Couplers such as a sleeve coupler and a split joint pin are also available as illustrated in the advertising material of Burton's Scaffolding International for "UNIQUE" scaffold couplers. However, these couplers require the use of tools for assembly.
The present invention is directed to a staging system having a hand rail coupling system for quick, easy and toolless coupling of coaxially aligned hand rail sections.